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o u n o DOI: 10.4172/2090-4541.1000138 s J and Applications

Research Article Open Access Geothermal Energy Potentials and Technologies in Nattaporn Chaiyat1*, Chatchawan Chaichana2 and Fongsaward S. Singharajwarapan3 1School of Renewable Energy, Maejo University, Chiang Mai, Thailand 2Department of Mechanical Engineering, Chiang Mai University, Chiang Mai, Thailand 3Groundwater Technology Service Center, Chiang Mai University, Chiang Mai, Thailand

Abstract This paper presents a concept for using the geothermal energy in Thailand. The geophysical properties and the suitable technologies are considered; moreover the prototypes of the suitable technology have been constructed and tested the system performances. The potential of 97 hot springs in Thailand are classified into three groups as high, moderate and low potential. Organic rankine cycle is selected for 12 high potential hot springs to generate electricity 3,909 kWe. Absorption chiller and 8 moderate potential hot springs could be produced the total cooling capacity 304 kW and the payback period is 22 months. Central drying room and 8 moderate potential hot springs could be used in the heating process at 406 kW and the payback period is 15 months. Drying room integrated with vapor compression heat pump is represented for boosting 26 low potential hot springs. The upgrading heat around 2,002 kW could be used for drying the agricultural products 200 Ton/d which the payback period is 29 months. It could be found that the geothermal energy potential in Thailand could be developed from 46 hot springs to be used for heat and power at around 6.6 MW.

Keywords: Geothermal energy; Organic rankine cycle; Heat pump around 61-80°C in China had studied by Aneke [17]. R-134a ORC system; Drying room; Absorption chiller. system was chosen to produce electricity and the system efficiency was around 8.8%. Introduction For the cooling technology, an absorption chiller is presented Geothermal energy is one type of renewable energy which the by various literatures. Kanoglu and Cengel [18] reported economic Thailand government sets a geothermal policy to increase the power evaluation of geothermal power generation, heating, and cooling. It generation to be 1 MW in 2021. Department of Mineral Resources found that geothermal heating and geothermal absorption cooling were of Thailand [1] reports 112 hot springs in Thailand. In 2008, Chiang revenue higher than geothermal power generation about 3.1 times and Mai University (CMU) [2] also reported 97 potential of hot springs in 2.9 times, respectively. Kececiler et al. [19] simulated the absorption Thailand and classified them into three groups as high, moderate and refrigeration cycle by using hot spring in Sivas, Turkey as heat source. low potential which is shown in Figure 1. For high potential hot spring, The simulation results also shown that hot spring in Sivas did not the surface water temperature is higher than 80°C. Moderate potential be used efficiently in . Kairouani and Nehdi [20] hot spring refers the surface water temperature between 60-80°C and presented a novel combined refrigeration system which was absorption low potential hot springs represents the surface water temperature system cascaded with conventional compression system. The modified is lower than 60°C. Thus, the aim of this research is to study the system increased the efficiency around 37-54% which was similarly the appropriate technologies for using geothermal energy in Thailand. research of Ayala et al. [21], Seara et al. [22] and Kairouani and Nehdi [23]. For technology to generate electricity, the various literatures are For technique for drying process, Chaiyat and Chaichana [24] presented such as Chaiyat and Chaichana [3] reported using high presented 2 types of drying processes which are a central drying room temperature hot spring at higher than 90°C to generate the electricity and a geothermal heat pump for drying room. The central drying room by using a binary system and a thermoelectric module. Combs et al. used hot spring to direct supplied into the drying room. For geothermal [4] studied the small geothermal power plant in America and Japan at heat pump, a R-290 vapor compression heat pump for upgrading hot capacity around 100-1,000 kW. The technologies of the slim hole and spring temperature around 40-50°C to be hot water around 70°C binary-cycle technology were selected to use for the off-grid area. And, for using in the drying room. Heat pump dryer was found to be the environment affect from the geothermal power plant was lower than an effective equipment with low energy consumption as reported the fossil power plant which was similarly Brophy [5], Kose [6] and by Singharajwarapan and Chaiyat [25] which used low potential hot Dagdas [7]. For the simulation studies, the selection of suitable working spring at temperature around 50°C to generate hot water temperature fluids for the organic rankine cycle (ORC) system was the hot issue around 70°C for the drying room. Pendyala et al. [26], Chou et al. [27], which had many reports to study this topic such as Hettiarachchi et al. [8], Schuster et al. [9], Guo [10], Sauret et al. [11], Liu et al. [12], Edrisi et al. [13], Li et al. [14], and Rodriguez et al. [15]. It was found that the suitable working fluid of those results were different because the system *Corresponding author: Nattaporn Chaiyat, School of Renewable Energy, Maejo University, Chiang Mai, Thailand, Tel. +6653-875-461; E-mail: [email protected] conditions of each study were different. But the most suitable working fluid of those studies introduced R-134a and R-245fa. In generating Received August 01, 2014; Accepted September 23, 2014; Published September electricity process, the ORC system was compared with a Kalina cycle 30, 2014 in term of efficiency. Guzovic et al. [16] studied the geothermal energy Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal to power plant in Croatia. The high temperature hot spring at 175°C Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139 was supplied to binary system which of organic rankine cycle and kalina cycle. The simulated results shown the ORC cycle had a higher Copyright: © 2014 Chaiyat N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted thermal efficiency and energy efficiency compared with the kalina use, distribution, and reproduction in any medium, provided the original author and cycle. Moreover, a low potential geothermal at hot water temperature source are credited.

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

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heat pump is combined with the drying room at surface hot spring temperature lower than 60°C. For the hot spring temperature lower than 60°C, the use in entertainment processes such as sauna and hot pool are introduced, after that, hot spring is leaved to the environment. Organic rankine cycle Figure 3 shows the main components of the ORC system which are boiler, turbine, generator, condenser and pump. In the conventional ORC, high temperature heat is absorbed at the boiler (QB) at temperature around 80-120°C which in this study is hot spring. After that the working fluid at the high pressure and temperature enters to the turbine (state 1) for producing the electricity at the generator (WTur). Next, the working fluid at the low pressure (state 2) is condensed at the condenser by cooling fluid at temperature around 30-40°C. The working fluid in liquid phase (state 3) is pumped to the boiler (state 4) and the new cycle is started again. Absorption chiller Absorption heat pump is one type of heat pump at using heat as the main energy which having 2 types are absorption chiller for cooling process and absorption heat transformer for boosting high temperature heat.

Figure 1: Location map of hot springs in Thailand.

Clements et al. [28], Young et al. [29] and Sadchang [30] also reported using single-stage vapor compression heat pump in the drying processes.

Duddumpudi [31] presented CO2 heat pump to generate hot water which reduced the severe environmental problems causing by synthetic refrigerants which corresponded with Stene [32] and Whitea [33]. From the literatures review, the various techniques are applied with hot spring. But, hot springs in Thailand are different with other geothermal resources. Thus, the main objective of this work is to study the suitable technique for using with each geothermal energy potential in Thailand. Moreover, the prototypes and case studies of each Figure 2: The concept of cascade useful for geothermal energy. technique in Thailand are presented and tested for evaluating the system performances. And, the physical properties of hot springs in Thailand are used to analyze the appropriate technology of each geothermal energy potential. System descriotions and equations Figure 2 shows a cascade useful concept for geothermal energy as based on hot spring temperature. For high potential hot spring, the surface hot spring temperature at higher than 80°C is presented to generate electricity by oganic rankine cycle. For moderate potential at temperature between 60-80°C, the various technologies could be apply with the moderate hot spring temperature which are the absorption chiller for cooling process and an central drying room for Schematic diagram of organic rankine cycle. drying process. For low potential hot spring, the vapor compression Figure 3:

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

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Figure 4 shows a schematic diagram of absorption chiller, at the Vapor compression heat pump for drying room generator, a binary liquid mixture consisting of a volatile component (absorbate) and a less volatile component (absorbent) is heated at a A conventional technique to upgrade low temperature heat to a medium temperature around 80°C. Part of the absorbate boils at a high higher temperature level is heat pump system. The common method pressure (PC) and a generator temperature (TG) at state 1. The vapor could be performed by vapor compression heat pump (VCHP) which fluid at concentration around 90% of absorbate is purified to be 100% the main components are compressor, condenser, evaporator and of absorbate by analyzer and rectifier at state 2. The pure absorbate expansion valve as shown in Figure 6. The working fluid has a low condenses in the condenser at a condenser temperature (TC) to be boiling temperature. At state 1, the fluid in vapor phase is compressed liquid at state 3. After that, the absorbate in liquid phase is throttled in the compressor to state 2 and the vapor condenses in the condenser at to the evaporator at state 4 of which an evaporator pressure (PE) is a high pressure and temperature to be liquid at state 3. The liquid is then lower than that of the condenser. The evaporator is heated at a low throttled to a low pressure at state 4 via the expansion device and the temperature (TE) around 0-20°C and the absorbate in form of vapor temperature drops down thus the fluid could absorb low temperature enters the absorber which has the same pressure as the evaporator at heat at the evaporator where the fluid boils at low temperature to be state 5. Meanwhile, liquid mixture from the generator, at state 6 is sent vapor again and the new cycle restarts. through a solution heat exchanger at state 7 into the absorber to the low pressure at state 8 through expansion device. In the absorber, the strong Materials and Methods solution absorbs the absorbate vapor and the weak solution leaves the Organic rankine cycle absorber at state 9 at a medium temperature (TA) around 40-50°C which is same the condenser temperature (TC). The weak solution at For high potential geothermal energy, hot spring temperature at state 9 from the absorber is then pumped to the high pressure through more than 80ºC has been introduced to generate electricity. At the the solution heat exchanger at state 10 into the generator again at state present, only one geothermal electricity is available in Thailand at Fang 11 and new cycle restarts. District, Chiang Mai Province. The technology used is organic rankine cycle with 300 kWe capacity of power plant as shown the descriptions Drying room in Table 1. A schematic diagram of geothermal drying room is shown Figure 5. Hot spring flows through a piping tube at point 1 to a heat exchanger at From Table 1, it could be found that the ORC power plant of Fang, point 2. A blower at point 3 is used to drive low temperature air through Chiang Mai uses the reservoir heat source from 86 m of hot spring hole the heat exchanger to be hot air at point 4. The high temperature heat to generate electricity. Thus, in this study, the reservoir temperature is flowed to drying area, where agricultural products are contained will be evaluated by the geochemistry of surface hot spring. After that, at point 5. After that hot air transfers heat to the products, the air the surface and reservoir temperature are used to find out the potential temperature will decrease while the air humidity will increase. For of geothermal power plant in Thailand combined with the system reducing the air humidity, the fresh air from outside is conducted to performance of Fang geothermal power plant. reduce the air humidity in the drying room via a small window at point 6 while the high humidity air is released to the ambient via a top duct at point 7.

Figure 5: A schematic diagram of central drying room.

Schematic diagram of vapor compression heat pump. Figure 4: Schematic diagram of absorption chiller. Figure 6:

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

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Absorption chiller Devices Type Properties · Thickness 3 in Cold room Isowall For moderate potential geothermal energy, the hot spring · Size 3.6 m x 3.6 m x 3 m temperature between 70-80ºC has been suggested to use in cooling · Capacity 16 kW Flooded shell and · Shell diameter 150 mm process. The cooling unit in this study is absorption cooling system Generator as shown a schematic diagram in Figure 4. A prototype of 10 kW tube heat exchanger · Tube size 9.525 mm x 850 mm x 40 tube · Heating area 1.016 m2 ammonia-water absorption chiller is designed and constructed to freeze Steel column of · Purified fluid to 99.95% of ammonia Analyzer the agricultural products in a well- insulated room. Mae Jan hot spring, analyzer · Size 100 mm x 1,100 mm Chiang Rai, Thailand with having the hot spring temperature around · Capacity 1 kW Shell and tube 98ºC from 56 m of slim hole is used to test the cooling performance of Rectifier · Shell size 150 mm x 200 mm heat exchanger the absorption chiller. The descriptions and photographs of the testing · Tube size 9.525 mm x 3,000 mm unit are shown in Table 2 and Figure 7, respectively. For the testing · Capacity 11.2 kW Plate heat Condenser · Size 110 mm x 300 mm x 50 plate results, the geothermal energy potential will be presented with the exchanger · Heating area 1.25 m2 absorption technique by the physical data of hot spring in Thailand. Receiver Vertical type · Volume 0.5 m3 Drying room Fin and tube · Capacity 11.2 kW Evaporator heat exchanger · Heating area 1.25 m2 For moderate potential hot spring, the surface water temperature · Capacity 15.3 kW between 60-80ºC has been also suggested to use in drying process as Shell and tube · Shell size 150 mm x 850 mm Absorber shown the system descriptions in Figure 5. The geothermal drying heat exchanger · Tube size 9.525 mm x 26,000 mm room is developed to dry the agricultural products in a well-insulated · Heating area 0.98 m2 room. Mae Jan hot spring, Chiang Rai, Thailand as shown in Figure Table 2: Descriptions of the cold room and absorption chiller. 6(b) is also used to test the heating performance of drying system. The descriptions and photographs of the testing unit are shown in Table 3 and Figure 8, respectively. Finally, the testing results of prototype will be used to predict the guidelines of the geothermal drying room in Thailand. Drying room by using single-stage vapor compression heat pump For low potential hot spring, the surface water temperature lower than 60ºC has been used in drying process by using vapor compression heat pump (VCHP) to upgrade heat to be around 70°C and supply into drying room. The working steps of the drying room with heat pump (a) The absorption chiller unit system start with the hot water enters the system as shown in Figure (b) Mae Jun hot spring, Thailand 9. The hot water transfers heat to the working fluid, which evaporates Figure 7: The prototype of absorption chiller at Mae Jun hot spring, Thailand. accordingly. The resultant vapor is then pressurized by the compressor. After that, upgrading heat is extracted at the condenser and sent into heating coil in the drying room. The air inside the room is then heated Devices Properties by the heating coil. · Thickness 3 in Dryer room The prototype of R-123 VCHP is set with the well-insulated testing · Size 3.3 m x 4.8 m x 3.2 m room. Hot spring temperature around 55ºC from 85 m of slim hole, · Fin and tube heat exchanger Heating coil · Size 2.413 m x 1.197 m · Piping tube API 40, 1/2 in Properties Data · Power 5 hp Motor Operation system Organic Rankine Cycle (ORC) · Speed 1,450 rpm Working fluid R-601a (Isopentane) Blower · Diameter 1.2 m 1 Hot spring flow rate (L/s) 16.5 (75% of maximum flow rate) Table 3: Descriptions of drying room and equipment. Slim hole deep (m) 86 Hot spring temperature entering ORC (ºC) 115 Huai Mak Liam hot spring, Chiang Rai, Thailand is used to test the Hot spring temperature leaving ORC (ºC) 77 integrated unit. The descriptions and prototypes of R-123 heat pump Cooling water flow rate (L/s) 72.2 and testing room are shown in Table 4 and Figure 10, respectively. Cooling water temperature entering ORC 20 Drying room by using two-stage vapor compression heat (ºC) pump Gross electrical power (kWe) 300 Total electrical power (kWe) 200 In this study, the 2-stage vapor compression heat pump is used to

Table 1: Descriptions of Fang geothermal power plant [34]. upgrade hot spring temperature around 40-50°C to be around 80-85°C Remark : 1Maximum hot spring flow rate is the reservoir flow rate which is for the drying room. R-134a and R-123 are chosen as the working fluids around 10 times of the surface hot spring flow rate. in the 2-stage heat pump system. Huai Mak Liam hot spring, Chiang

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

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Devices Type Properties · Thickness 3 in Drying room Isowall · Size 3.3 m x 4.8 m x 3.2 m Indirect Heat Gasket plate heat exchanger · Capacity 15 kW Exchanger (hot spring to hot water) · Heating area 0.8 m2 · Capacity 0.37 kW Hot water pump1 Centrifugal pump · Flow rate 80 L/min Hot water Vertical steel tank · Capacity 10 L receiver 1 and 2 · Capacity 3 kW Compressor Open type compressor 3 (a) Heating coil and blower in drying room · Volume flow rate 25 m /h

(b) Hot spring piping system Plate heat exchanger · Capacity 20 kW Condenser 2 Figure 8: The prototype of drying room at Mae Jun hot spring, Thailand. (R-123 to hot water) · Heating area 3.65 m Plate heat exchanger · Capacity 15 kW Evaporator (R-123 to hot water) · Heating area 2.88 m2 Expansion valve Orifice type · Capacity 15 kW

Table 4: Descriptions of geothermal drying room and 2-stage heat pump components.

Devices Type Properties

Drying room Isowall · Thickness 3 in · Size 2.4 m x 4.8 m x 2.3 m Hot water pump Centrifugal pump · Capacity 0.37 kW Figure 9: Schematic diagram of the geothermal drying room by using 2-stage · Flow rate 60 L/min VCHP. Expansion tank Vertical steel tank · Capacity 10 L Compressor 1 Hermetic compressor · Capacity 2 kW R-134a · Volume flow rate 11.46 25 m3/h

Compressor 2 Open type compressor · Capacity 3 kW R-123 · Volume flow rate 25 m3/h

Condenser Plate heat exchanger · Heat capacity 20 kW

(R-123 to hot water) · Heating area 1.64 m2

Economizer Plate heat exchanger · Heat capacity 15 kW (R-134a to R-123) · Heating area 2.39 m2 Evaporator Plate heat exchanger · Heat capacity 8.75 kW 2 (hot water to R-134a) · Heating area 1.64 m

Expansion Orifice type · Capacity 20 kW · valve 1 thermostatic orifice 04 Pressure ratio 3.305 (a) The prototype of single-stage VCHP (b) the geothermal drying room Expansion Orifice type · Capacity 12 kW Figure 10: The photograph of geothermal drying room by using single-stage valve 2 thermostatic orifice 06 · Pressure ratio 3.87 VCHP. Sub cool 1 Plate heat exchanger · Heat capacity 2 kW (hot water to R-134a) · Heating area 0.64 m2 Sub cool 2 Plate heat exchanger · Heat capacity 8 kW (hot water to R-123) · Heating area 0.64 m2 Dying coil Plate heat exchanger · Capacity 20 kW (hot water to air) · Heating area 2.88 m2

Table 5: Descriptions of geothermal drying room and 2-stage heat pump components. Results and Discussions Generating electricity process by using ORC technology

Figure 11: Schematic diagram of the geothermal drying room by using The geothermal resources in Thailand are evaluated and compared 2-stage VCHP. with Fang geothermal power plant to assess the primary energy potential. The results stated that 12 geothermal resources are capable to generate the electrical power as shown in Table 6. Rai, Thailand with having the surface water temperature around 45°C from 30 m of the slim hole is used to test the heating efficiency From Table 6, it could be seen that 12 high potential hot springs of the prototype. A schematic diagram of geothermal drying room at the surface temperature higher than 80°C could be produced the integrated with 2-stage VCHP is shown in Figure 11. The descriptions total electricity around 521 kWe. Moreover, if the reservoir energy is extracted, the higher power energy could be generated compared with and photographs of testing unit are shown in Table 5 and Figure 12, the surface potential. Table 6 also shows the electricity from reservoir respectively. energy at around 3,909 kWe.

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

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Hot springs Province Temp (°C) Quartz1 (°C) Flow (L/s) ORC2 (kWe) ORC3 (kWe) Mae Jan1 Chiang Rai 93 163.35 1.1 18.39 137.94 Mae Jan2 Chiang Rai 93 160.75 5.56 92.89 696.67 San Kam Phaeng Chiang Mai 88.5 147.64 5.56 92.89 696.67 Doi Sa Ket Chiang Mai 96.3 144.65 0.26 4.35 32.60 Fang Chiang Mai 98.1 142.59 1.56 26.08 195.62 Pong Duead Chiang Mai 95 142.59 5.56 92.89 696.67 Thep Pha Nom Chiang Mai 98.9 141.70 1.65 27.59 206.91 Pong Pa Mae Hong Sorn 87.4 126.40 0.23 3.85 28.84 Mueang Paeng Mae Hong Sorn 96 125.42 5.56 92.89 696.67 Nong Haeng Mae Hong Sorn 81.1 122.07 3 50.16 376.20 Chae Son Lampang 83.7 120.69 1.1 18.39 137.94 Mae Jork Phare 80.7 116.35 0.05 0.84 6.27 Sum 521 3,909

Table 6: Geothermal resources with electricity generating. Remarks: 1Reservoir temperature from quartz (maximum stream loss) equation.

TGS = [1,522/(5.75 – log(SiO2))] – 273.15 [35] SiO2 based on the study result of CMU [2]. 2 ƞ ƞ ° Q = ORC mCpΔT, ORC is 10% [34] m: Mass of flow rate, Cp is 4.18 KJ/Kg-K, ΔTis hot difference temperature at approximately 40 C [34] and density of hot string is 1,000 Kg/m3 3 ƞ Q = ORC mCpΔT, m is 75% maximum hot Spring flow rate which the minimum value is 10 times of the surface hot spring flow rate [34].

T (°C) T (°C) T (°C) T (°C) T (°C) air,i,,E air,o,E CW,i HW,i HW,o 9.86 6.04 24.78 97.95 85.88 T (°C) Q (kW) Q (kW) 1 EER2 (kW /kW ) G G E COP th e 91.17 15.13 9.56 0.63 0.59

Table 7: The average testing data of absorption chiller. 1 2 Remarks: COPAB = QE/QG and EERAB = QE/(QG + WSys)

Figure 13: The photograph of evaporator at the air temperature in cold room around 1 oC.

cooling per month, 24 hours per freezing set. At the time of assessment

a) The 2-stage VCHP b) the geothermal drying room with the construction cost about 20,000 USD and the payback period is 22 months. Figure 12: The geothermal drying room by using 2-stage VCHP. Table 8 shows 8 moderate potential hot springs at temperature between 70-80°C at the most found in the northern area of Thailand. Cooling process by using absorption chiller Moreover, Table 8 also shows the total cooling capacity at around 304 kW of absorption chiller from 8 hot spring resources. Absorption chiller is constructed and tested the cooling efficiency. Table 7 shows the testing data of ammonia-water single-stage Drying process by central drying room absorption refrigeration. It could be seen that the absorption unit could be decreased the minimum air temperature in the cold room The central drying room is constructed with a dimension of 3.30 to be around 1°C as shown in Figure 13 which is given hot spring m×4.80 m×3.20 m at capacity of about 3 Ton (3,000 kg) of agricultural temperature around 98°C. The testing results is also shown the EERAB products. It generates room temperatures to be over 80°C. The hot water at around 0.6 which is lower than the other researches because a big size transfers heat into the heating coil in the drying room. The air inside the of refrigerant pump at power consumption around 1.03 kWe is taken in room is heated by the 20 kW heating coil. Efficiency test of the empty the absorption unit. drying room showed that the room temperature increases from 25°C to be over 80°C within 5 minutes. The heating efficiency of drying room is For economic evaluation, the cold room at capacity 3,000 kg by around 80% (η ) with the water temperatures entering and leaving using the 10 kW absorption system is also carried out with 10 sets of Drying

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

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the drying room and operation system cost about 11,000 USD and the Temp Flow Absorption1 Drying2 Hot spring Province payback period at around 15 months is found. (°C) (L/s) (kW) (kW) From the testing data of the central drying room, it could be seen Pu Feang Chiang Rai 73.3 4.5 113 150 that if moderate potential hot springs as shown Table 8 are used in the Sop Pong Chiang Rai 79.3 0.44 11 15 drying process, the total heating capacity at around 406 kW could be used for extracting moisture of the agricultural products. Pong Phra Bat Chiang Rai 73.1 3.8 95 127

Thung Pong Chiang Mai 75 1.19 30 40 Drying process by vapor compression heat pump

Tha Pai Mae Hong Sorn 78.9 1.44 36 48 The drying room integrating with the heat pump system is constructed giving an intake capacity of about 3 Ton (3,000 kg) of Mae Um Long Mae Hong Sorn 78.8 0.19 5 6 agricultural products. It generates the air room temperatures between Pho Thong Tak 74.8 0.1 3 3 60-75°C. From the testing results as shown in Table 9, it could be seen Klong Plag Pau Phangnga 74.8 0.48 12 16 that efficiency test of the empty drying room showed that the room Sum 304 406 temperature increased from 25°C to be 70°C within 3 hours. The energy efficiency ratios (EERs) of the VCHP and the drying room

Table 8: Geothermal resources with cooling potential. 1 Remarks: Q = EERAB mCpΔT, EERAB is 0.59, m is the surface hot spring flow rate, Descriptions Data Cp is 4.18 Mass flow rate of hot spring (kg/s) 0.22 kJ/kg·K, ΔT is hot spring difference temperature approximately 10 oC and density o of hot spring is 1,000 kg/m3 Hot spring temperature entering at the evaporator ( C) 44.80 22 Hot spring temperature leaving at the evaporator (oC) 37.60 Q = ƞDrying mCpΔT, ƞDrying is hot spring difference temperature approximately 10ᵒC 3 and density of hot spring is 1,000 kg/m . Heat capacity of hot spring (kW) 6.52 Mass flow rate of hot water entering at the condenser (kg/s) 1.03 Hot water temperature leaving at the condenser (oC) 84.10 Hot water temperature entering at the condenser (oC) 79.40 Heat capacity of hot water (kW) 20.67 Electrical power consumption of 2-state VCHP (kWe) 4.62 Electrical power consumption of drying room (kWe) 7.37 EERVCHP (kWth/kWe) 4.17 EERDrying room (kWth/kWe) 2.57

a) Cherry before drying process b) Cherry after 12 hours of drying process Table 10: The average testing results of geothermal drying room and 2-stage Figure 14: The photograph of cherry in drying room at hot air temperature VCHP. around 95 oC. Temp Heat pump1 Hot spring Province Flow (L/s) (oC) (kW) Descriptions Data Pong Na Kham Chiang Rai 65.9 0.52 28 Mass flow rate of hot spring (kg/s) 0.75 Houy Mhak Leam Chiang Rai 56.6 7 376 Hot spring temperature entering at the evaporator (°C) 49.60 Pha Sert Chiang Rai 66.2 2.38 128

Hot spring temperature leaving at the evaporator (°C) 48.61 Huay Sai Khaow Chiang Rai 56.5 1.96 105 Pong Arong Chiang Mai 52.3 0.78 42 Heat capacity of hot spring (kW) 3.10 Ban Yang Pu Toa Chiang Mai 51.7 0.2 11 Mass flow rate of hot water entering at the condenser (kg/s) 1.33 Non Klang Chiang Mai 68.8 3.5 188 Hot water temperature leaving at the condenser (°C) 72.80 Pa dauk Chiang Mai 55.8 0.81 44 Hot water temperature entering at the condenser (°C) 71.40 Mal Li Ka Chiang Mai 68.1 0.25 13 Heat capacity of hot water (kW) 7.78 Pha Bong Mae Hong Sorn 65.5 0.67 36 Electrical power consumption of single-stage VCHP (kWe) 2.58 Wiang Nuea Lampang 61.2 0.94 50

Electrical power consumption of drying room (kWe) 5.60 Ban Pong Nam Ron Lampang 56.2 1.12 60 Ban Pan Jen Phare 53.8 0.23 12 EERVCHP (kWth/kWe) 3.02 Wad Slang Phare 65.7 0.8 43 EERDrying room (kWth/kWe) 1.39 Ban Pong Lam Pang Sukhothai 55.6 0.16 9 Table 9: The average testing results of geothermal drying room and single-stage VCHP. Pa Ja Lern Tak 60 0.36 19 Boek Lueng Rachburi 57.3 5 269 of the system as 98°C and 87°C, respectively. And, Figure 14 also shows Pong Long Ranong 56.2 0.26 14 the drying product at 12 hours of cherry. Ban Khao Noi Surat Thani 52.1 1.53 82 For economic results, the evaluation is also carried out with 15 sets Rat Ta No Go Sai Surat Thani 61 2.38 128 of drying per month, 24 hours per drying set. At the assessment with Table 11: Geothermal resources with boosting heat potential.

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

Page 8 of 9 are 3.02 kWth/kWe and 1.39 kWth/kWe, respectively, with the water Maejo University, Chiang Mai, Thailand, Department of Mechanical Engineering, temperatures entering and leaving of the VCHP system as 49.60°C and Chiang Mai University, Thailand and Groundwater Technology Service Center, Chiang Mai University, Chiang Mai, Thailand for supporting testing facilities. Highly 48.61°C, respectively. Economic evaluation is also carried out with acknowledge to the Ministry of Energy for the budget support. 15 sets of drying per month, 24 hours per drying set. At the time of assessment with the construction budget of about 20,000 USD, the References payback period is 13 months. 1. Department of Mineral Resources (2014) Geothermal Energy Resources. Table 10 shows the average testing results of the 2-stage vapor 2. Department of Alternative and Efficiency (2008) Study for conservation and development of low potential hot springs for multipurpose compression heat pump combining with the geothermal drying room. usage. Chiang Mai University. It could be found that hot spring temperatures entering and leaving at 3. Chaiyat N, Chaichana C (2009) Drying Room from Geothermal Energy, In: the evaporator are around 44.80°C and 37.60°C, respectively, and heat Proceeding of Seminar on the 10th Conference on Energy, Heat and Mass capacity of hot spring is around 6.52 kW. While, the heat pump system Transfer in Thermal Equipments and Processes, Chiang Rai, Thailand. could be upgraded heat to be hot water temperature around 84.10°C at 4. Combs J, Garg SK, Pritchett JW (1997) Geothermal slim holes for small off-grid the useful heat capacity and the EERVCHP around 20.67 kW and 4.17 power projects. Renewable Energy 10: 389-402. kWth/kWe, respectively. The drying room efficiency in term of EER is 5. Brophy P (1997) Environmental advantages to the utilization of geothermal around 2.57 kWth/kWe. For economic results, the investment costs of energy. Renewable Energy 10: 367-77. the drying room and the 2-stage VCHP are 25,000 USD and the cost 6. Kose R (2005) Research on the generation of electricity from the geothermal of electrical power consumption is around 1,000 USD/y with 15 sets resources in Simav region Turkey. Renewable Energy 30: 67-79. of drying per month, 24 hours per drying set. While the revenue from 7. Dagdas A (2007) Heat exchanger optimization for geothermal district heating the geothermal drying room is around 10,500 Baht/y, thus the payback systems: A fuel saving approach. Renewable Energy 32:1020-1032. period is around 29 months. 8. Hettiarachchi HDM, Golubovica M, Worek WM, Ikegamib Y (2007) Optimum From the testing results of heat pump dryer, it could be found that design criteria for an Organic Rankine cycle using low-temperature geothermal heat sources. Energy 32: 1698-1706. 26 low potential hot springs as shown Table 11 could be developed for boosting heat process at the total heating capacity around 2,002 kW, 9. Schuster A, Karellas S, Karl J (2005) Simulation of an innovative stand-alone solar desalination system with an Organic Rankine Cycle. International Journal and the agricultural products as around 200 Ton/d could be dried in of Thermodynamics 10. the heat pump drying room. 10. Guo T, Wang HX, Zhang SJ (2011) Fluids and parameters optimization for a From the above results, it could be noted that 46 hot springs in novel cogeneration system driven by low-temperature geothermal sources. Energy 36: 2639-2649. Thailand could be useful in generating electricity process, cooling process, heating process and boosting heat process. Moreover, 6.6 MW 11. Sauret E, Rowlands AS (2011) Candidate radial-inflow turbines and high- useful capacity from geothermal energy could be developed in Thailand. density working fluids for geothermal power systems. Energy 36: 4460-4467. 12. Liu B, Riviore P, Coquelet C, Gicquel R, David F (2012) Investigation of a two Conclusions stage Rankine cycle for electric power plants. Applied Energy 100: 285-294. From this study, the conclusions are as follows: 13. Edrisi BH, Michaelides EE (2013) Effect of the working fluid on the optimum work of binary- flashing geothermal power plants. Energy 50: 389-394.

1. The geothermal energy potential at around 6.6 MW could be 14. Li T, Zhu J, Zhang W (2013) Comparative analysis of series and parallel developed in Thailand by 4 technologies which are organic rankine geothermal systems combined power, heat and oil recovery in oilfield. Applied cycle for generating electricity, absorption chiller for cooling Thermal Engineering 50: 1132-1141. process, central drying room for heating process and drying room 15. Rodriguez CEC, Palacio JCE, Venturini OJ, Silva LEE, Cobas VMD, et al (2009) Exergetic and economic comparison of ORC and Kalina cycle for low integrating with vapor compression heat pump for boosting heat temperature Antonio Yock. In: Proceeding of Seminar on Short Course on process. Surface Exploration for Geothermal Resources, El Salvador. 2. For the ORC technique, 12 high potential hot springs could be 16. Guzovic Z, Loncar D, Ferdelji N (2010) Possibilities of electricity generation in the Republic of Croatia by means of geothermal energy. Energy 35: 3429-3440. generated electricity from the surface heat and the reservoir heat are around 512 kWe and 3,909 kWe, respectively. 17. Aneke M, Agnew B, Underwood C (2011) Performance analysis of the Chena binary geothermal power plant. Applied Thermal Engineering 31: 1825-1832.

3. Absorption chiller and 8 moderate potential hot springs could be 18. Mehmet K, Yunus AC (1999) Economic evaluation of geothermal power produced the total cooling capacity around 304 kW and the payback generation, heating, and cooling. Energy 24: 501-509. period of absorption chiller is 22 months. 19. Abdullah KH, Ibrahim A, Ayla D (2000) Thermodynamic analysis of the absorption refrigeration system with geothermal energy: an experimental study. 4. Central drying room and 8 moderate potential hot springs could be Energy Conversion and Management 41: 37-48. used in the heating process at the total capacity around 406 kW and 20. Kairouani L, Nehdi E (2006) Cooling performance and energy saving of a the payback period of the central drying room is 15 months. compression- absorption refrigeration system assisted by geothermal energy. Applied Thermal Engineering 26: 288-94.

5. For the boosting technique, 26 hot springs could be upgrading 21. Ayala R, Heard CL, Holland FA (1997) Ammonia/lithium nitrate absorption/ heat around 2,002 kW by using the drying room integrating with compression refrigeration cycle part 1: simulation. Appl Therm Eng17: 223-233. the vapor compression heat pump and the payback period of this 22. Seara JF, Sieres J, Vazquez M (2006) Compression-absorption cascade method around 29 months. refrigeration system. Applied Thermal Engineering 26: 502-12. Acknowledgement 23. Kairouani L, Nehdi E (2005) Thermodynamic Analysis of an Absorption/ Compression Refrigeration System Using Geothermal Energy. American The authors would like to acknowledge the School of Renewable Energy, Journal of Applied Sciences 2: 914-919.

J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139 Citation: Chaiyat N, Chaichana C, Singharajwarapan FS (2014) Geothermal Energy Potentials and Technologies in Thailand. J Fundam Renewable Energy Appl 4: 139. doi: 10.4172/2090-4541.1000139

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J Fundam Renewable Energy Appl ISSN: 2090-4541 JFRA, an open access journal Volume 4 • Issue 2 • 1000139